tseries (version 0.1-1)

pacf: Partial Autocorrelation Function

Description

Computes the sample partial autocorrelation function of x up to lag lag. If pl is TRUE, then the partial autocorrelation function and the 95% confidence bounds for strict white noise are also plotted. Missing values are not handled.

Usage

pacf (x, lag = length(x) - 1, pl = TRUE, ...)

Arguments

x

a numeric vector or time series.

lag

a scalar lag parameter.

pl

a logical indicating whether the partial autocorrelation function is plotted.

...

additional arguments to plot.tsparam.

Value

• A "tsparam" object.

Details

The partial autocorrelations are obtained from Yule-Walker estimates of the successive autoregressive processes. The algorithm of Durbin is used (see Box and Jenkins (1976), p. 65).

References

P. J. Brockwell and R. A. Davis (1991): Time Series: Theory and Methods, 2nd Edition, Springer Verlag, NY, pp. 98-102.

G. E. P. Box and G. M. Jenkins (1976): Time Series Analysis, Forecasting and Control, Holden-Day, San Francisco, pp. 64, 65.

See Also

tsparam

Examples

n <- 1500
e <- rnorm (n, sd=2.25^2)  # Example 8.2.1 from Brockwell and Davies (1991)
x <- double (n)
x[1] <- 0
x[2] <- 0
for (i in 3:n)
{
  x[i] <- 0.5*x[i-1]+0.2*x[i-2]+e[i]
}
x <- window(ts(x),start=501)
plot (x)
acf (x, 40, type="o", ylim=range(-1,1))
pacf (x, 40, type="o", ylim=range(-1,1))